Chair back



FIG. 1 is a perspective view of a chair back showing my new design;

FIG. 2 is a plan view of thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a front view thereof;

FIG. 6 is a left side elevation view thereof, the right side elevation being a mirror image thereof;

FIG. 7 is a plan view of a chair back showing an alternate embodiment of my new design;

FIG. 8 is a rear elevation view of a chair back showing the alternate embodiment of my new design;

FIG. 9 is a bottom view of a chair back showing the alternate embodiemnt of my new design;

FIG. 10 is a front elevation view of a chair back showing the alternate embodiment of my new design; and,

FIG. 11 is a left side elevation view of a chair back showing the alternate embodiment of my new design. 

The ornamental design for a chair back, as shown and described. 